UPSC CSE Prelims
Basics of Biotechnology Previous Year Questions (PYQs)

Detailed Explanation:

Answer: Option 4 — All four

All four statements about mushroom properties are scientifically accurate. Mushrooms exhibit a remarkable diversity of biological properties that have been documented and utilized across medicinal, recreational, agricultural, and ecological contexts.

✅ Statement 1 – Correct: Medicinal mushrooms like Reishi (Ganoderma lucidum), Turkey Tail (Trametes versicolor), and Lion's Mane (Hericium erinaceus) contain bioactive compounds with immune-modulating, anti-inflammatory, and neuroprotective properties.

✅ Statement 2 – Correct: Psychoactive mushrooms containing psilocybin (such as Psilocybe cubensis) produce hallucinogenic effects and are being researched for therapeutic applications in treating depression and PTSD.

✅ Statement 3 – Correct: Insecticidal mushrooms like Metarhizium anisopliae and Beauveria bassiana produce compounds toxic to insects and are used as biological pest control agents in agriculture.

✅ Statement 4 – Correct: Bioluminescent mushrooms such as Mycena chlorophos and Panellus stipticus produce light through enzymatic reactions involving luciferin and luciferase, creating a natural glow in dark forest environments.

📝 Short Notes: Properties of Mushrooms

Detailed Explanation:

Answer: Option 3 — 1 and 3 only

This question tests the fundamental structural differences between plant and animal cells. Statement 2 is incorrect because both plant and animal cells possess a plasma membrane, which is a universal feature of all cells.

✅ Statement 1 – Correct: Plant cells have rigid cellulose cell walls for structural support and protection, while animal cells lack cell walls and only have a flexible plasma membrane.

❌ Statement 2 – Incorrect: Both plant and animal cells have plasma membranes (cell membranes); this is a fundamental feature present in all living cells, controlling the movement of substances in and out of the cell.

✅ Statement 3 – Correct: Mature plant cells typically contain one large central vacuole for storage of water, nutrients, and waste, whereas animal cells have multiple small vacuoles that are less prominent.

📝 Short Notes: Plant vs Animal Cells

Detailed Explanation:

Photosynthesis converts light energy (free energy) from the sun into chemical energy (potential energy) and stores it in the bonds of glucose molecules.

The process uses carbon dioxide and water as raw materials and releases oxygen as a byproduct, while the stored energy in glucose can later be used by plants and other organisms.

Detailed Explanation:

Calcium triggers muscle contraction by binding to troponin, which allows actin-myosin interaction.

Iron enables oxygen transport via myoglobin and supports ATP production in mitochondria for sustained muscle contraction.

Sodium maintains membrane potential and initiates action potentials that trigger muscle fiber contraction.

All three minerals (Calcium, Iron, Sodium) are essential for muscle contraction. Hence, option 4 is correct.